Abstract

The present work investigated Hastatella radians Erlanger, 1890 (type species), and H. aesculacantha Jarocki & Jakubowska, 1927, isolated from Chongming Island, Shanghai, China, based on light microscopy observations of live individuals, silver staining and molecular phylogeny methods. Hastatella radians is characterized by its size (about 30–75 μm long, 25–70 μm wide), two girdles of ectoplasmic processes, infundibular polykinety 3 (P3) composed of two rows of unequal length and terminating beyond adstomal end of P2, 8–22 transverse silverlines between peristome and trochal band, and 5–9 between trochal band and scopula. The infraciliature of H. aesculacantha is described for the first time, and we improved its diagnosis: cell size about 25–52 × 20–41 μm in vivo; four girdles of ectoplasmic processes; P3 two-rowed, outer row much shorter than inner one; 5–7 silverlines between peristome and trochal band and four or five between trochal band and scopula. Phylogenetic analyses based on SSU rDNA sequences revealed that Hastatella is monophyletic and has a close relationship to Astylozoon enriquesi .